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Restructuring and Other Charges - Schedule of Restructuring and Other Activities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 01, 2022	Apr. 02, 2021	Apr. 01, 2022	Apr. 02, 2021
Restructuring Reserve [Roll Forward]
Beginning balance			$ 14,031
Net(Credits) Charges			14,929
Payments and other			(13,338)
Ending balance	$ 15,622		15,622
Restructuring Cost and Reserve [Line Items]
Other net charges			162,600
People & Places Solutions
Restructuring Reserve [Roll Forward]
Real estate impairment and other transformation activities			71,000
Restructuring Cost and Reserve [Line Items]
Real estate impairment and other transformation activities			71,000
CH2M HILL Companies, Ltd.
Restructuring Reserve [Roll Forward]
Net(Credits) Charges	108,164	$ 30,347	177,524	$ 78,741
Restructuring Cost and Reserve [Line Items]
Loss related to settlement	$ 91,300		$ 91,300